Impacts of Frequency Dependent Mutual Coupling and Channel Errors on Digital Beam Forming Antenna Performance

Ilir F. Progri, B. W. Nicholson, David M. Upton, Wallace E. Vander Velde

Abstract:	This paper presents the results of a computer simulation which models a digital beam forming adaptive antenna for suppression of RF interfer-ence. The simulation includes a weight compu-tation using the Sample Matrix Inversion (SMI) adaptive algorithm and an SINR performance criterion (cost function). The complex (I, Q) signals composed of narrow band and/or broad band interference sources (jammers) and GPS signals are corrupted by fre-quency dependent mutual coupling and channel errors. These digitally sampled signals are used to form a sample correlation matrix, which is then used to compute the antenna weights for a given steering vector. These weights are quan-tized and applied to the corrupted, digitally sam-pled signals using a complex multiplication. Signal types, location, and strength, antenna ge-ometry, and receiver parameters form the simu-lation inputs. The presence of mutual coupling and channel errors can also be specified by simulation inputs. The antenna performance is given in terms of the inverse cost function (J/S) versus number of samples with/without mutual coupling and/or channel errors. The results demonstrate that the digital beam-forming antenna performance is only slightly affected by the presence of fre-quency dependent mutual coupling and channel errors, thereby alleviating the need for extensive calibration that would be required in an analog antenna implementation.
Published in:	Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998) September 15 - 18, 1998 Nashville, TN
Pages:	275 - 283
Cite this article:	Progri, Ilir F., Nicholson, B. W., Upton, David M., Velde, Wallace E. Vander, "Impacts of Frequency Dependent Mutual Coupling and Channel Errors on Digital Beam Forming Antenna Performance," Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998), Nashville, TN, September 1998, pp. 275-283.
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